Electrothermostat.



T. LIDBERG.

ELEGTROTHERMOSTA'T.

APPLICATION FILED MAY19.1914.

Patented J an. 25, 1916.

Z Z6556 'fjadoli l%? MBIA PLM IOGRAPH co., WASHINGTON D c n STATES PATENT FFICE.

'IIODOLF 'LIIJBERG, or oIIIc G ILLINoIs, ASSIGNOR To CHICAGQSURGICAL &

ELECTRICAL so, or CHICAGO, ILLINOIS, A CORPORATION or ILLINOIS.

To all whomz't may concern: I

Be it known that I, TIODOLF LIDBERG, acitizen of the United States, residing at Chicago, in the county of: Cook and State of Illinois, have invented certain new. and

useful Improvements in Electrothermostats, of which the following is a specification.

My invention relates to improvements in electrothermostats.

One of the general objectsof my invention is to improve theaccuracy and sensitiveness of thermostats to control electric circuits.

A variation of a few degreeswill destroy or V stunt the germs and render the incubator .useless for the purpose intended. Therefore, a reliable heat-responseand controlling means, operated by the heat which it controls, must be sensitive, quick of action, without lag either wav and dependable.

A better understanding of my invention may be obtained from a consideration of the following description; when takenin connection with the drawing, wherein;

Figure 1 is a plan view of the thermostat; Fig. 2 is a central vertical section, taken on line 2-2 of Fig. 1. Fig. 3 is a transverse section, taken on line 3-3 of Fig.1.

In all theviews the same reference characters are employed to indicate similar parts.

The device, as depicted'in the drawing, is of such size as to give very practical results. The body portion consists of two flanged rings 5 and Gsecured around their periphery, as bv screws 7. of which there may be any desirable number. Between the outward projecting flanges, 8-78 of said rings, is included the heat responsive diaphragm, generally indicated by 9, consisting'of a sheet of material having a high co-eflicient of expansion, such as hard rubber 10, and a sheet of hard drawn copper, bronze or the like, 11, or any other suitable material hav j Specification of Letters Patent. Application filed Ma 19, 1914. Serial No. 839,619.

Patented Jan. 25, 1916.

- ing a lower expansive heat coeflicient. The sheets or disks are held together, as by two circumferentially extending rows of rivets,

12 and 13, and around their periphery they are bound together, by the screws 7 and l t, which pass through the two flanged rings 5 and 6 and through the composite diaphragm. The screws 14:14 also pass through brackets, 15, upon which to support the device, on the walls or'the floor of the incubator. One of the brackets is provided With an electric terminal screw, 16, by means of which the copper disk 11 may be connected in an electric circuit by screws passing through the perforations 1717. A bar 18 is transversely fixed across the diameter of the diaphragm and insulatedly supported by screws 19, which pass through the rings 5 and 6 and the diaphragm 9. An electric terminal screw 20 is threaded into the end of the bar 21 is threaded through the bar 18, near the longitudinal center thereof, and is provided on its inner end with a contact 22, adapted for-cooperative relation with the contact 23 of the metal disk 11 of the diaphragm. A friction brake, for the purpose of maintaining the screw 21 in its adjusted position, consists of a spring 24, bearing upon the face of the screw 21, and secured to the bar 1.8, as by screws 25. This spring has frictional bearing with the screw and maintains it in whateverposition it may be placed, the adjustment of the screw being necessary to change the degreeof temperature to bemaintained.

The device is to be placed within an incubator, with an electro-responsive means for producing heat, which the thermostat In many instances temperature of the incubator up to the desired point, the outer disk 10, of hard rubher, will expand to a greater extent than the inner metal diaphragm 11 thereby causing the composite diaphragm 9 to be deflected near its central zone, to the right or dished outwardly, so that the movable contact 23 is carried away from the relatively stationary contact 22, the circuit is opened between the contacts and the lamp will be extinguished. atmosphere, less than one quarter of a degree in practice will cause the diaphragm 10 to be contracted to a greater extent than the diaphragm l1, and the parts will be returned to circuit-closing position, and the lamp will thereby be again lighted so that it will raise the surrounding atmosphere to its normal temperature. The device is so sensitive that there is a trembling connection between the contacts 22 and. 23 and therefore the lamp is rarely caused to burn at its normal rated capacity.

A condenser may be connected between the contacts 22- and 23 to subdue the sparks, if it is found necessary, in fact; however, where a single incandescent lamp, requiring not over half an ampere, is used. I have found the spark between the contacts to be so small as to become practically negligible without the use of a condenser.

Turning the adiusting screw 21 clockwise will have the effect of nressinothe diaphragm 9 outwardly and therefore it will require a greater heat, within the incubator, to cause separation of. the contacts 22 and 23 than when the pressure produced by the screw against the diaphragmis not so great,

The slightest chilling of the and consequently the critical temperature to be maintained may thus be varied.

It is manifest that other means than the rivets l2 and 18 may be employed for connectingthe disks of the diaphragm together, but it 'is essential that they should be maintained in intimate contact between their centers and their peripheral edges, so that in every instance they may be moved together and not susceptible of separate or inde Jendent movement.

aving described my invention, what I claim is A device of the character described comprising two flanged diaphragm supporting rings; a diaphragm comprising a hard rubber disk and a metal disk clamped together at their peripheries, between said rings; means for securing said disks together within the areainclosed by said rings; an electric contact near the center of said diaphragm, movable therewith; an insulated bar crossing said diaphragm and secured to said rings; and an adjustable contact carried by said bar for electric cooperation with the contact relatively movable by said diaphragm.

In testimony whereof I hereunto set my hand in the presence of two subscribing witnesses.

TIODOLF LIDBERG. In the presence of 1 031 31; Barr, MARY F. ALLEN.

Copies of this patent may be. obtained for five cents each, by addressing the Commissioner of Patents. Washington, D. C. 

